Thu Apr 27, 2017 4:34 am
Hello Antonio,
Nothing has changed in Hauptwerk itself (in at least the last few versions/years) regarding how or when audio drivers are started/stopped or handled, or the way that Hauptwerk asks the audio interface to set the sample rate when it starts the audio driver (which has always been the case, since Hauptwerk v2).
If there is indeed a difference in the MOTU's behaviour between your current Mac and another one, then it must be due to something other than Hauptwerk per-se. For example, if you were only using 48 kHz sample sets on your previous Mac then the issue wouldn't have arisen. Or perhaps an older version of the MOTU driver behaved differently. Conceivably also the time that the MOTU hardware/driver takes to change sample rate depends upon the network topology (since the MOTU AVB interfaces are designed for networked audio), but I don't know; MOTU would be the best people to advise on what factors might or might not be relevant. (Perhaps even completely disabling all wired and wireless networking, and BlueTooth, might make it change rates faster, but again I don't know.)
My MOTU 16A interfaces are currently set up on a Mac partition running OS X 10.10.5 (connected to the Mac only via USB, with no network connections from the MOTUs to the computer or to any other network devices), and mine still take about 15 seconds for any sample rate change to take effect, during which time they produce no sound. The same happens in any audio application (not just Hauptwerk), so it isn't a Hauptwerk issue per-se (except indirectly inasmuch as Hauptwerk needs the audio interface to change sample rates) -- the issue is just that the MOTU hardware/driver take a long time to switch sample rates. (It isn't something that inconveniences me personally, for the way that I work, but I can certainly appreciate that it might be an inconvenience for others.)
As I mentioned, in the longer-term we do aim to add an option for Hauptwerk to perform sample rate conversions in real-time, as work-around for audio interfaces that don't like switching sample rates (although real-time sample rate conversions inevitably involve some trade-offs in terms of audio quality and/or latency, and CPU overheads). However, in the meantime, probably the only people who could address the issue with the MOTU AVB interfaces being so slow to change sample rates are MOTU themselves.
Best regards, Martin.
Hauptwerk software designer/developer, Milan Digital Audio.